Fans of notorious US hip-hop group Insane Clown Posse have been officially classified as a gang. A new FBI document has categorised the Juggalos as a "loosely-organised hybrid gang," citing the group's violence, criminal activity and "gang-like behaviour".

Fans of the Insane Clown Posse have called themselves Juggalos for more than two decades, developing a reputation for face-paint, Faygo soda, and a scepticism toward magnets. Although based in the United States – the ICP are from Michigan – it has become a worldwide movement; a UK Facebook group has more than 600 members.

Unfortunately for harmless fans of horrorcore rap, Juggalos are now officially "of concern to law enforcement," according to the FBI's 2011 National Gang Threat Assessment report. Juggalos have been tied to a string of recent crimes, including a shooting in January and the assault of a homeless man last year. "Open source reporting suggests that a small number of Juggalos are forming more organised subsets and engaging in more gang-like criminal activity," the report alleges. "Transient, criminal Juggalo groups pose a threat to communities due to the potential for violence, drug use/sales, and their general destructive and violent nature."

While the FBI report only mentions the Insane Clown Posse in a footnote, ICP are not just a soundtrack for the subculture. The group is named after an ICP song, The Juggla, and the Detroit-based rappers organise the annual Gathering of the Juggalos, which attracts more than 20,000 fans. Despite their scary reputation, the Posse has even been described as a Christian group. After a fan called Jacob D Robida shot his girlfriend in 2006, ICP's manager spoke out against such violence: "Anyone that knows anything at all about Juggalos knows that in no way, shape, or form would we ever approve of this type of bullshit behaviour," he wrote.

Although the FBI's gang designation is unlikely to have an immediate effect on ICP, its fans, or friends such as Jack White, many Juggalos are upset. In just a few days, more than 200 people have signed a petition asking the FBI to revise their decision. "Juggalos are a family that have each other's backs," explained a supporter based in Tennessee. "They're people who would die for somebody they haven't even met."